Improvement in paving-blocks



V w.1". PRENTISS.

PAVING-BLOCK. No. 171,318. Patented-116121 1875.

AX z v I UNITED STATES PATENT OFFICE.

WILLIAM F. PRENTISS, OF NORTHAMPTON, MASSACHUSETTS.

IMPROVEMENT IN PAVING-BLOCKS.

Specification forming part of Letters Patent No. 171,318, dated December 21, 1875; application filed June 7, 1875.

' all but one side of the cement or composition,

is formed, as shown in Fig. I. to have four corners or legs, b, whose outside surfaces are coincident with the sides of a square of which the tread or top of the block' 61 would form one side, and which legs proceed from the top d of the block in such shape as to leave the inner surface of the top, when the block is in verted, in the form of sheds sloping from the interior and between the legs to the outside of the block. Screwed into the center of the top d, and extending beneath the top parallel to the legs, and of equal length, is the bolt 9, which is provided at its lower end with the nut h.

The topsurface or tread I may be corrugated or roughened to any desired extent, and is made only thick enough to avoid being cracked by any jarring above it.

p In order to form the block, the frame B is inverted and a mold fitted over the legs b to inclose them, and between the walls thus formed the concrete or cement is filled in.

When this filling D solidifies the nut h is run on the bolt g, to tighten it against the sloping interior surface of the tread and legs.

Should the material used to form the filling D be mixed with water, the form, as shown, of the bottom wall of the tread permits the superfluous water to escape, to so facilitate the hardening of the material, which, as before mentioned, is then compressed to come in contact with all parts of the interior surface of the frame B. I

The blocks thus formed can be laid in a soft bed of the material of which they are partially composed, either in contact with each other, or having space between them to be also filled in with the soft material forming the bed, which bed, when it sets or hardens, unites with the bottoms and sides of the blocks, and the whole pavement becomes in effect a solid mass, re-enforced on its surface byan iron face, which, in its turn, is evenly and immovably riveted to the bed.

For the purpose of combining with the frame B to form the block, I prefer cement, as shown in the drawing, for a material, although common mortar, asphaltum, or similar substances may be used, and the blocks may be set upon a hard bed, if desired.

What I claim is A paving-block formed of the metallic frame B, constructed and united, substantially as described, to thefilling D.

WILLIAM F. PRENTISS. 

